Steam-boiler.



No. 729,757. PATENTED JUNE 2,1903. T. A. GILLESPIE.

STEAM BOILER.

APPLICATION FILED o0'r.22, 1902.

no menu. 2 SHBETS-SHEBTL No. 729,757. PATENTED JUNE 2, 1903.

T. A. GILLBSPIB.

STEAM BOILER. APNJOATION FILED OCT. 82, 1902. 4 N0 MODEL. 2 SHEETS-SHEET2.

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Patented June 2, 1903.

PATENT OFFICE.

THOMAS A. GILLESPIE, OF WEST ORANGE, JERSEY.

STEAM-BOILER.

SPECIFICATION formingpart of Letters Patent No. 729,757, dated June 2,1903.

Application filed October 22, 1902- serial No. 128,233. (No model.)

To all whom it may concern.-

Be it known that I, THOMAS A. GILLEsPIE, a citizen of the United States,residing at \Vest Orange, county of Essex, State of New Jersey, haveinvented certain new and useful Improvements in Steam-Boilers, of whichthe following is a specification, reference being had to the drawingsaccompanying and forming part of the same.

My invention relates to steam-generators, and has for its object toproduce a boiler which shall avoid certain of the defects com: monlyfound in boilers as heretofore constructed. Steam-generators of theboiler type are usually built up of a large number of small platesriveted together, and considerable difficulty is experienced in makingthe numerous seams tight and strong enough to withstand heavy pressures,especiallyin the transverse or circumferential seams, in which thelapped plates must be fitted to each other with great nicety. hightemperature of the furnace presents f urther disadvantages. The doublethickness of metal at each joint not only requires an appreci ablylonger time for the heat to penetrate to the interior, but the underlap,being thus screened, doesnot expand as rapidly as the outer one, whichis exposed directly to the heat, with the result that both tensile andshearing strains are produced, tending directly to open the seams. Myinvention, however, obviates these defects, for the reason thatlongitudinal joints only are employed, transverse or circumferentialseams being entirely dispensed with, and for the further reason thatnone of the seams is directly exposed to the flames. Thesecharacteristics are secured by making the shell of two or more plateseach the full length of the boiler, a con struction which will be morereadily under stood by referring to thedrawings, in WhlGl1' Figure l isa section of my boiler and a furnace to heat the same. Fig. 2 is aperspective view of the shell without heads. Fig. 3 shows a convenientmethod of securing the heads to the shell, and Fig. 4 is a sectionshowing a boiler made of three plates.

The shell shown in Figs. 1, 2, and 3 consists of two plates 1 2, benttransversely to their The exposure of such seams to the longitudinalaxes and having their edges upset or thickened, as at 3 4-. These arelocked firmly and securely together by means of locking-bars 5, whichare bent downaround the upset edges. Not only is such a joint cheaper,but extended tests and practical use have shown it to be superior to ariveted seam as to strength and tightness.

The boiler is arranged in any convenient manner over a furnace, forexample, as shown in Fig. 1. As will be seen, the lock-bar joints areremoved. from the directheat of the firebox, so that both adjacent edgesof the upper the material has not been weakened by 1111- merousrivet-holes. The heads may also be se= cured to the shell by means oflock-bars, as

will be seen in Fig. 5, in which a locking-ring 6 engages the upset endsof the plates 1 and 2 and the edge of the flanged head 7.

The size of boiler, which may be made of two plates, is of courselimited by the size in which plates can be made; but if it becomesnecessary for this reason to use three sheets they may be utilized, asillustrated in Fig. 4. In this case the joints are directly exposed tothe fire but there at most only two such, and the troublesome transverseseams are absent. Furthermore, the edges of the sections are ,bothcovered by the same amount of metal in the lock-bar, so that both areheated equally, thus still avoidin the strains before mentioned.

The forms shown I consider convenient; but it will be understood, ofcourse, that my invention is capable of many embodiments, and it istherefore not limited to those described. For example, the boiler may bemade of a single plate bent till the edges meet and a single locking-barto join them. This I con sider clearly within the scope of my invention.

hat I claim is'-= 1. A boiler having no transverse seams be tween theheads having the contiguous plate edges thickened or upset and alongitudinal I exposed to the direct heat of said furnace, aslocking-bar firmly gripping said edges, as and and for the purposes setforth.

for the purposes set forth. r 1 "1 2. The combination with a furnace, ofa PHOMAS (TILLLSPIE' 5 longitudinally-j ointed boiler having no trans-WVitnesses:

verse joints between its heads having its 10ngitudinal joints formed bylocking-bars un- M. LAMSON DYER, S. S. DUNHAM.

